Goals: Like the ill-fated Mars 4, launched four days earlier, Mars 5 was designed to orbit Mars, taking pictures and conducting remote-sensing experiments on the atmosphere and surface, and to serve as a communications relay for the Mars 6 and 7 landers.

Accomplishments: Mars 5 achieved orbit around Mars, but its mission was cut short by an apparent micrometeoroid puncture which caused the main instrument compartment to slowly depressurize. During the 16 days of operational orbiting, the spacecraft returned atmospheric data and transmitted 43 usable photos and 5 panoramas of the Martian surface. Some surface features suggested erosion caused by flowing water.